Distillation of tar or pitch and apparatus therefor



Feb. 20, 1934. s, P MlLLER 1,947,485

DISTILLATION OF TAR OR PITCH AND APPARATUS THEREF'OR ATTORN EYS S. P. MILLER Feb. 20, 1934.

DISTILLATION OF TAR OR FITCH AND APPARATUS THEREFOR Filed Aug. 9, 1929 4 Sheets-Sheet 2 INVENTOR WM M BY ATTORNEYS Feb. 20, 1934. s p M|| ER 1,947,485

DISTILLATION OF TAR OR FITCH AND APPARATUS THEREFOR Filed Aug. 9. 1929 4 Sheets-Sheet 3 ATTORNEYS Feb. 20, 1934. 5 p, MlLLER 1,947,485

DISTILLATION OF' TAR OR FITCH AND APPARATUS THEREFOR ATTORN EY5 Patented Feb. 20, 1934 UiTED STATES DIsrILLA'rIoN 0F TAR on PITCH AN APPARATUS y'rHEREroR Stuart Parmelee Miller, Englewood, N. J., as-

signor to The Barrett Company, New York, N. Y., a corporation of New Jersey f Application August 9, 1929. Serial No. 384,665

11 Claims.

This invention relates to improvements in the distillation of tar or pitch and the production of coke therefrom.

According to the present invention, the tar or pitch to be distilled is brought into intimate and direct contact with hot gases, for example hct coal distillation gases or other hot coal gasication gases at a suiciently high temperature to distill the tar or pitch and remove substantially all of the oil constituents therefrom and to leave a coke residue, and the oils distilled from the tar or pitch are removed with the gases employed for the distillation and are subsequently condensed therefrom.

It has been proposed to distill tar or pitch to produce coke in externally heated stills, but such distillation, when carried out by the commonly known methods, is acompanied by a considerable decomposition of oil constituents of the tar or pitch distilled, with corresponding reduction in the yeld of distillate oils, and increase in the coke residue. Particularly at the higher temperatures required for the distillation of pitch to produce coke, the decomposition of heavy distillable constituents, such as resins, greases, etc., is very considerable, but even at lower temperatures appreciable decomposition of distillable oils takes place when the distillation is carried out in externally heated stills of the commonly lmovvn types.

The present invention provides an improved process in which a materially increased yield of distillate is obtained from a tar or pitch, and in which objectionable decompositon of distillabie constituents is reduced to a minimum.

The word tar in the following includes raw tar containing a certain percentage of water, dehydrated tar partly or entirely freed of water, and stripped tar from which a part of the more volatile constituents have been removed. The word pitch refers to the distillation residues of tar.

According to the present invention, I provide a still into which the tar or pitch to be distilled is introduced, and I heat the tar or pitch and eiiect its distillation by introducing into the still, and into di ect and intimate contact with the tar or pitch therein, hot gases at a sufciently high temperature to effect distillation of the tar or pitch and the production of coke therefrom. The production of coke from pitch by this method is in part the result of Volatilization of pitch components and in part the result of thermal decomposition oi pitch components to form a carbonaceous residue. The distillate oils are taken off in vapor form with the gases and the mixed gases and vapors are cooled to condense the distillate. The present process is advantageously carried out in a continuous manner, with continuous introduction of tar or pitch to be distilled, and with continuous production and discharge oi coke from the apparatus, as Well as continuous withdrawal A and condensation of distillate.

The distillation o1" the tar or pitch, according to the present process, may be carried out at coal distillation plants, and with the use of hot coal distillation gases, such as the gases from the ovensV of a coke oven plant. The coke oven gases leave the individual ovens at a high temperature around 600 to 700 C. or higher. I make use or" such gases by collecting them and passing them while still at a high temperature into the still and into contact with the tar or pitch to be distilled. By withdrawing the gases from individual ovens through insulated lines and preventing the cooling of the gases before they reach the still, they can be employed at practically their maximum temperature for the distillation and coking operation. In the case of a coke oven plant, the coking still can be located on top of the block, or at one end of the block, and with an insulated pipe leadingthe gases from a sufficient number of the individual ovens to the coking still for carrying out the distillation and the coking operation. Or, instead of collecting the gases from several ovens and then passing the combined gases intothe still, the gases from individual ovens lmay be passed directly into the still and at diierent parts of the still.

The present process can be carried out with coke oven or other tar, introducing the tar into the still, and Acarrying out the distillation ina single operation. In this case, the entire distillate will be carried off from the coking still with the gases. Instead of distilling tar, the tar may be separately distilled to produce pitch, and the pitch subjected to further distillation and coking according to the present process. In suchY case,the pitch is charged into the coking still and is subjected to distillation by direct contact with the hot gases.

A particularly valuable application of the invention involves the distillation of tar in two stages, in the first of which it `is subjected to distillation by direct contact with hot coal distillation ygases to produce a pitch of Amediumor of high melting point, for example a pitch of `around 300 F. 011400" F. melting point, and the resulting pitch is then subjected to furtherdistillation in a'coking still by'direct contact with hot coal distillation gases to produce coke and additional distillate. zIn such a two stage distillation, the

distillate from the two stages can if desired be separately condensed. The distillate from the coking still, when high melting point pitch is charged into it, will be an unusually heavy distillate which, when cold, will be solid or semi-solid in character. In condensingsuch a heavy distillate, carev should be taken to avoid cooling to too low a temperature such as would solidify the coke stills is avoided, the large amount of inert' gases allow reduction of the temperature at which the heavy distillate is removed from the still, and,

as a result, an unusually high yield of distillate can be obtained. Whereas, by ordinary methods of distillation, yields of distillate oils of around 50 to`60% or somewhat more are obtained on the distillation of tar to coke, the improved process of the present invention enables a yield of as high as 80 or 90% of the tar to be obtained in the formv of valuable distillates, with corresponding reduction in the amount of coke produced. During the coking of the pitch residue decomposition of the non-volatile pitch constituents and of some of the very high boiling volatile constituents goes on. Fixed gases are generated. They are of value as fuel gases. When `coke oven gases or other gases which are to be subsequently employed as fuel gases, are used for converting pitch to coke according to this invention, the fixed gases generated during the Vconversion blend with the coke'oven gases, etc. andare valuable products of my process.

The coking still employed in the present process 'is advantageouslyone in which the tar or pitch is kept agitated and in which the coke as it is being formed is kept agitated and in which the operation is carried out continuously so that the coke is continuously discharged in a broken upor nely divided condition` from the apparatus. An apparatus provided with rotating ory reciprocating stirrers oragitators` or VScrapers can be employed, which will keep the tar or pitch agitated and which, as the pitch graduallychanges tor' coke, will keep thersemivrcokeor coke agitated and expose fresh surfaces thereof to contact With the hot gases. Arotating cylindrical vessel can also be employed into one end of which the tar or pitch to be distilled is introduced, and from the other end of which the coke is discharged, and through which the hot coal distillation gases pass countercurrent to the pitch and coke. In such a rotating still, the prevention of the formation of a solid layer of coke can be effected by providingagitating elements or tumblers which serve to break up the 'coke and maintain it in a loose or divided form such that it can discharge from the apparatus. 1 The coke produced by the present process is a valuablefuel product.

The distillate obtained by the present process Will vary with the character of the material distilled. ,Where tar is distilled and the distillation carried to completion in a single still, the entire distillate Will be obtained as vapors admixed with `thegases employed for the' distillation, and, on

cooling such gases and vapors, the total distillate can be condensed together, or fractionally condensed to give a plurality of products. Any tar constituents carried by the gases employed for the distillation will be to some extentl separated Vfrom the gases inthe still but to'a'considerable extent will remain in the gases leavigth'e still.

On cooling these gases, any tar or pitch constituents which they contain will be separated with the condensate from the distillation. The gases employed for thedistillation may be hot coal distillation gases which contain tarry or pitchy constituents such as hot coke oven gases or gas retort gases or coal gasication gases such as hot carburetted water gas, or hot coal gasification gases substantially free from such entrained impurities, such as hot water gas, for example may be employed.

When the distillation is carried out in two stages, the distillate from the rst stage, in which tar is distilled to produce pitch, can be kept separate and recovered as a creosote oil, or fractionally condensed to give a heavier creosote oil and a lighter carbolic oil, etc. If the gases employed for the distillation of the tar to produce pitch contain tar or pitch constituents and they distillation is carried out with thorough scrubbing of the gases, the distillate Will be a relatively clean oil, that is, free or substantially so from entrained impurities. Y

The distillate from the coking still, when pitch is supplied to it, will bea heavy distillate, and care should be taken to condense it at temperatures which will keep it fluid until it is removed from the condensers. Where gases, such as hot coke oven gases, which contain entrained tarry and pitchy constituents, are employed for coking the pitch, the distillate obtained will comprise tarry and pitchy constituents which will separate from the gases on cooling. Where a clean distillate is desired direct, the gases and vapors leaving the coking still may be cleaned at a high temperature in any manner adapted to the removal of tarry and pitchy particles from such high temperature gases. On cooling these cleaned gases clean distillate will be obtained.

Theheavy distillate from the coking still can be fractionally condensed to recover a heavy distillate of a semi-solid or solid character, or this heavy distillate can be condensed in admixture With lighter oils and recovered as a composite liquid product made up in part of the heavy distillate and in part of lighter oils. Where two successive stills are employed for two stage disboth stills can be combined together to give a l composite total distillate which may represent as high as 80 or 90% of the tar distilled. Where gases containing entrained tarry and pitchy particles are employed for the distillation, and a combined clean oil distillate from both stages is desired, the gases and vapors from the coking still may advantageously be passed through the still of the rstV stage where tar is distilled to pitch, and'by intimate and intensive spraying of the gases and vapors in this still with the tar, the

gases will be detarred and the tar will be distilled to pitch. When this is done part of the least volatile constituents may be reabsorbed by the pitch in the still of the irst stage, and thus be conveyed back to the coking still. In this cycle ."v

such constituents may in part be decomposed and coked. On subsequent cooling of the detarred gases, a clean total distillate will be obtained.

Instead of condensing a total distillate, the distillate can be fractionally condensed and selected i' fractions employed for creosoting or other purposes.

The invention will be further described in connection with'theaccompanying.drawings which illustrate in a somewhat conventional and diayso grammatic manner, suitable apparatus for carrying out the improved process.

Fig. 1 shows a plan view, schematic in part and with part broken away, of a coke oven plant equipped with means for the continuous distillation of tar to coke in two stages, viz. distillation oi the tar to pitch and then distillation of the pitch to coke, by hot coal distillation gases;

Fig. 2 is an elevation in section of one form of the colring still, tar still and coke receiver of Fig. 1;

Fig. 3 is a vertical section of the coke still on the line 3-3 of Fig. 2;

Fig. 4 is a vertical section of the tar still on the line 4 4 of Fig. 2;

Fig. 5 is a vertical section of the hot condenser;

Fig. 6 shows a plan view, schematic in part and with part broken away, of a coke oven battery equipped with different means for the distillation of tar to coke in two stages, by hot coal distillation gases;

Fig. '7 is a longitudinal section of the coke still of Fig. 6; and

Fig. 8 is a section of the tar still on the line 8-8 of Fig. 6.

The arrangement of the tar still and coke still shown in the drawings may be applied to a coke oven battery or to other coal carbonization or gasification plants, such as gas producer plants. gas retort plants, water gas plants, etc., with appropriate modications.

Fig. 1 shows means for distilling tar to coke by hot coke oven gases with countercurrent flow of the gases and the material being distilled. The coke oven battery 5 is shown as being equipped rwith uptake pipes 6, through which the coke oven gases pass trom the ovens to the collector main 7, whence they pass through the center-box 8 through the cross-over main 9 to condensers, etc. This may be the usual type of apparatus and is shown schematically.

At -the rear of the battery additional 'uptake pipes i0 are provided on selected ovens through which the gases from these ovens may be directed by the manipulation of valves'in the uptake pipes 6 and 10 into the coking still 11. Pitch from any suitable source, preferably in a fluid condition, -is fed to the coke still through the opening 12. In Fig. 1 the pitch is shown as coming directly and continuously the tar still 13, from which it is drawn orf through a suitable draw-off 14.

The co .e still is equipped with agitating means adapted to keep the pitch and the coke produced therefrom in motion during its passage through the still. For this purpose the still 11 is equipped with arms 15, provided with scraping shoes 16 and baiiles 17 which serve to prevent the building up or" pitch or semi-,coke on the arms, Scrapers and retort walls. Suitable mechanism 18 is provided for transmitting an oscillatory motion to vthe arms through the shaft 19.

The hot gases from selected ovens passing up through the uptakes carry the hot gases from the selected ovens into the still, cause distillation of volatile constituents therefrom, remove the 21 as coke. The revolving gate 24 is provided to control the rate of discharge from the chute 21. The hot coke is advantageously quenched in water as it leaves the still. For this purpose the tank 22 containing suflicient water to seal the end of the chute is provided. An endless conveyor 23 is also provided for removing the quenched coke from the tank 22 to a storage bin 25.

Other means for collecting and removing the coke may be employed. The coke, may, for eX- ample, be collected in a hopper sealed against loss of gas to the atmosphere. The coke may, by manipulation of suitable gates, be periodically removed.

Coal distillation gases, such as coke oven gases,

etc., contain particles of coke and pitchy particles, etc., known as tar fog which persist, at least to some extent, in the gases, even though the gases are passed through condensers or scrubbers of the ordinary type. The gases leaving the still 1l will ordinarily contain much of the "tar fog present in the gases as they enter the still from the ovens. In addition these gases leaving the still contain oil vapors present in the gases leaving the ovens and also vapors distilled from the pitch in the still 1l, as well as ammonia, etc., ordinarily present in coke'oven gases. The vapors distilled from the pitch comprise vapors of high boiling resinous and greasy materials which are solid or semi-solid at ordinary temperatures in an isolated state. By fractionally cooling the gases these resinous and greasy substances may be recovered as a separate fraction. However, if the gases are cooled as they leave the still 1l, the condensate or condensates produced will be contaminated by entrained solid and liquid impurities present in the gases leaving the ovens as tar fog, and possibly by some particles of pitch or coke carried over by the gases from the still 11. Although the gases may be cooled directly after they leave the still, and by fractional cooling using a suitable condenser, such as a hot condenser, a heavy resinous substance, as well as light and heavy tarry oils comprising creosote constituents and carbolic oil constituents, or one total tarry oil or dirferent tarry oil fractions may be obtained, the gases leaving the coke still are advantageously cleaned before being cooled, and the cleaning is advantageously done at a high temperature. Any suitable means for cleaning may be employed such as an electrical precipitator, a hot gas scrubber, etc.

In the drawings, means is shown for bringing the hot gases into contact with an intensive, nely divided spray of hot tar or pitch which detars the gases, removing substantially all entrained particles therefrom. In the drawings the detarring is done in the tar still. The hot gases are brought from the coke still l1 to the tar still 13 through the short main 27. This main is heavily insulated as at 28, and each piece of the equipment between the ovens and the hot condenser may advantageously be similarly insulated.

In the still 13 the gases are brought into contact with tar or partially distilled tar or pitch, which is distilled by the gases, and which, in turn, by intimate contact with the gases, detars them.

The tar is advantageously admitted to the still through sprays 29 in the settling tower 30. The tar may if desired be preheated in any suitable way. This preheating of the tar increases the unit capacity of the hot gases to distill tar and to coke pitch.

The higher the temperature to which the tar is preheated the smaller the quantity of hot gas required.

In the drawings, a roll 31 which dips to only a slight extent into the tar or pitch, located at one side of the still 13 and rapidly rotated by the motor 32, is provided for eiiecting the intensive spraying of the gases necessary to detar them and at the saine time to flush the walls of the distilling main to prevent accumulation of coke. Any spray of tar or pitch carried from the still l.; by the gases is removed by the baffles 34 and the tar sprayed from 29, and returns to the still 13.

The now of material through the tar still and then through the coke still, the quantity of gases passed through the stills, the temperatureto which the tar is preheated before entering the sprays 29, etc., are so regulated and the apparatus is so designed that the tar is distilled in the still 13 to pitch oi a melting point just less than that which might cause difliculties to arise due to coking of the pitch to an undesirable degree in the tar still, e. g., a melting point over 300 F. and even up to 350 F., and preferably not much higher. Where desirable, a portion of the pitch from the still may be drawn oi through the drawo 33', solidified, as by chilling with cold water from 34 and conducting away in gutter 35', and used for any desired purpose.

The detarred gases leaving the settling tower 30 through the main 35 carry vapors distilled from the tar in its conversion to coke. These vapors comprise constituents of lower and medium boiling points such as light oils, carbollc oil constituents, oresote oil constituents, and anthracene oil constituents as well as high boiling constituents of a resinous or pitchy character. The vapors may be condensed in one step to produce a total condensate, or they may be cooled in two or more steps.

The high boiling resinous or pitchy substances carried as vapors in the gases may be obtained as a separate fraction by passing the gases through' a hot condenser in which the temperature of the gases is reduced to the extent necessary to condense the desired high boiling constituents, but not suliciently low to condense other' oils which it is desired to carry over with the gases into the other condensers, and not suiiiciently low to cause solidiication or hardening of the high boiling resinous substances to such an extent as to cause clogging of the tubes of the condenser or the draw-oir for these substances. The drawof from the condenser may advantageously be steam-jacketed or at least heavily insulated.

Although other condensing means may be employed, in the drawings the gases are shown as passing first through the hot condenser 36, which is shown as an indirect condenser, then through another indirect condenser' 37 for removing other and somewhat lower boiling constituents, then through the direct condenser 38 where lower boiling constituents are removed and then through the exhauster 39. From the exhauster the gases are advantageously passed to means (not shown) for removing ammonia, light oils, etc., which may advantageously be accomplished in the means used for recovering theseconstituents from the gases passing through the'cross-over main 9 to the ordinary by-product recovery apparatus.

The drawings show the condensers 36 and 37 as comprised in one condenser tower. The gases enter at the bottom or" the tower and pass up through the hot condenser 36 which is here shown as of the indirect type in which the gases pass up through the tubes 40 Whichare surrounded .by a

sie. 1.

Ycoolingmedium of regulated temperature which may for example be a heatedgas, ora uid such as steam, which passes into the jacket through 42 and out at 41. Hot high boiling oil may be circulated through the condenser for removal of heat and may then be passed to a suitable heat `interchanger'for coolingbefore return to the condenser.

Cooling of the condenser may also be accomplished by supplying to it in regulated amount a liquid which will be Vaporized in the condenser and hence will remove heat as latent heat. The vapors may be conducted away, be condensed andthe condensate be returned for further vaporization and heat removal. The resinous materials which are condensed are withdrawn through ythe insulated draw-off 43 and collected in 44.

The gases then pass up through the gas passage 45 into the condenser 37 where high boiling oils are condensed and drawn 01T through 46 to the storage receptacle 47.

From this condenser the gases pass through the main 48 to the condensers 38 which are of the ordinary direct type in which the gases `are cooled with sprays of water or ammonia liquor. The clean lower boiling oils may be here collected as a single fraction comprising the carbolic oils, or two separate fractions may be collected. Where one fraction is collected the liquor from these condensers may be drawn'to the decanter 49 and K and the hot gases flow through the still countercurrent to one another. The gases leaving the coking still are detarred in the tar still 60 and the tar is distilled. The iiow oi tar and gases in this still 60 is concurrent. The hot gases are brought in direct contact with the fresh tar, and the nished ypitch leaves the still in contact with the vapor laden and somewhat cooled gases which have been employed for the distillation. As the nished pitch is not brought into Contact with the hottest gases, the pitch may be distilled to a melting point of 350 F., or '400 F. or higher without objectionable coking in the tar still.

In Fig. 6 a coke oven battery 5 with uptake pipes 6, collector main 7, center-box 8, and crossover main 9 are illustrated schematically as in Uptake pipes 5l situated at the rear of the battery are connected with a hot gas header 52 which collects the fresh hot gases from a number of ovens and introduces them into one end of the coking still through Vthe opening 53. y The ovens connected with the hot gas header through the uptake pipes 51 are also connected with the collector main 7 by means of uptake pipes 6. By properlyregulating valves in the uptake pipes 6 and the uptake pipes 51,the gases from these ovens may be directed either to the collector main 7 or to the hot gas header 52. The hot gases in passing through the still pass countercurrent to tor similar to that shown in connection with tank 22 of Fig. 1.

The hot coke oven gases enriched in condensable constituents leave the coke still 58 through the main 59 and are passed through the tar still 60 in which the hot gases are sprayed to remove entrained tar fog, etc. The gases leaving the coke stili. may be sent directly to condensers or may be cleaned in any suitable manner and then condensed. By passing the hot gases through the tar still 60, and detarring them thereinY by an intensive tar spray, the gases are detarred and the tar is distilled. The pitch produced is withdrawn from the still through the draw-cil 6l and all or a part of the pitch may advantageously be directed into the coke still 58 where the pitch will be converted to coke, althcugh it is to be understood that the coke still 58 may be utilized for treating pitch from another source than theV tar still 60. A portion of the pitch produced may be drawn off through 61', cooled with water fromy 62 and stored in 63.

The tar still in the drawingsr is shown as equipped with a roll 62 which is adapted to be rotated at high speed by the motor 63. By situating the roll so that it dips to only a slight extent into the tar or pitch which may be fed to the still through the pipe 64, the tar or pitch is sprayed up into the gases, the tar still is lled with a ne spray of tar or pitch thrown from the roll, and the walls of the still are continuously washed with a moving layer of tar or pitch. This spray detars the gases and the tar which may advantageously be preheated before entering the still is distilled by the direct contact between the tar and the gases. Additional hot coke oven gases may be admitted to the tar still through one or more uptake pipes 65 in order to maintain the temperature of the gases within the tar lstill above the dew point of the constituents which it is desired to drive over from the tar still into the condenser 65, although it will in general be more desirable to add such gases through the hot gas header 52 in order that they may be employed at maximum temperature for coking the pitch.

The hot gases coming from the coke still pass through the tar still where they are detarred and further enriched in condensable constituents. These gases are passed up through the settling tower 67 situated on top Yof the tar still and entrained particles of pitch carried from the still by the gases will settle out of the gases in this settling tower and return to the pitch within.

the still. The gases which are substantially free from entrained particles pass through the main 68 to the condenser 66. The main 59 and the other elements of the apparatus which the gases pass through in travelling from the .uptake pipes 51 to the condenser 66 may advantageously be heavily insulated to prevent cooling of the gases and possible condensation of oil constituents from the gases.

Although the Fig. 6 shows one condenser for cooling the gases to recover the oils carried by the gases, it is to be understood that fractional condensing means may be employed. The liquid collecting in the bottom of the condenser 66 is drawn off into the decanter 67'. From the decanter the clean oils are separated into the storage tank 68. From the condenser the gases pass through the exhauster 69 to means for recovering ammonia, light oils, etc.

By bringing the tar into intimate contact with the hot distillation gases in still 60 in the form of an intensive spray, and distilling the tar to pitch with a melting point of around 400 F., a yield of around 70 to 75% of clean oil distillate may be obtained. By coking this pitch with the hot gases in the coke still 58, and agitating the pitch in the still, and the coke as it is formed,- and vaporizing the volatile constituents `and iushing them from the still asthey are formed, an additional distillate of up to 5% or even as much as 15% will be obtained. y l

ln the drawings the invention is described more particularly as applied to distillation with hot coke oven gases. It is to rbe understood` that other hot gases, such as hot retort gases, hot water gas, hot producer gas, flue gases, superheated steam, etc. may be employed. After the gases employed 4for the distillation have been cooled for the separation of oils, they may be reheated and be used for further distillation where desired. Where the distillationV to coke is effected by hot water gas, steam or another,v gas which is free from or low in entrained impurities, the resulting gases on cooling will yield directly distillates which are free from or low in tar or pitchy constituents without first being sub- Y jected to a cleaning treatment. Tar may be distilled to coke, or pitch which may be pitch pro-Y duced as a part of the same operation by dis-` tillation of tar in hot coke oven gases or other hot gases or pitch from another source produced in the usual way may be distilled to coke.

Figs. 1 and 6 show coke stills from which the hotgases pass to tar stills in which tar is distilled to pitch which may then be fed to the coke stills, and in which the gases are detarred and enriched with lighter oils. Clean oil fractions or total distillates may be recovered from the enriched gases by condensation. Tar maylli) be distilled and coke produced in the coke still only. In this case tar will be fed direct` tothe coke still. It will be distilled by the hot gases, but where gases containing tarry or pitchy yconstituents are employed for the distillation thedistillate obtained will contain tarry or'pitchy matter since the hot gases will not be cleaned to the same degree as when they pass through` tar stills such as illustratedin Figs. 1 and 6. The

mil

gases will befenriched by the oil vapors resulting'lZO,

as to yield on cooling distillates suiciently low r in free carbon to allow their use as distillate oil for creosoting. Where tarry oils of` lowv vfree carbon content are desired for use as creosoting compositions, either the gases may bel enriched to a less degree, or the gases may be enrichedl'@v to a greater degree and tar may be blended with the resulting relatively clean oils to yield the desired creosoting composition. The process and apparatus described provide 4 for distilling tar or pitch in hot gases, e.v g. hot' 135 coke oven gases at substantially the temperature at which they leave the ovens for the production of coke, high yields of distillate oils, and valuable fuel gases where hot coal distillation or coal gasification gases are employed.

The coke produced by my process is a high grade coke, high in carbon content and low in ash, e. g. containing usually not over 1 to 2% ash, and in many cases not over 1/2 to 1% ash. It is produced continuously and may be produced in crushed or nodular form which may readily be prepared for sale by screening. llf the operation is conducted in a rotating retort with tumblers, e. g. balls or rods, nely crushedvv coke may readily be produced. It ordinarily Will not require crushing unless it be desirecto employ or market'it all in relatively small sizes. The Volatile` content of the coke may be regulated WithinVV wide limits by regulating the quantityA of the hot gases passed through the still. Cokes of varying degrees of combustibility may thus readily be produced for the special purposes to which such high grade materials are put.

I claimz- 1'. The method of distilling tar and producing coke,y gas, and distillate oils therefrom, which comprises subjecting the tar to distillation by spraying itV into hot coal gasification gases and then' further distillingaand decomposing the tar distillation residue by direct contact with hot coalgasication gases thereby producing coke, and cooling theY gases and vapors resulting from the distillation to recover distillates therefrom.

2. The continuous method of converting pitchl to coke, which comprises heating the pitch by direct contact with hot coal gasification gasesat a sufficiently high temperature to remove distillates from the pitch thereby producing coke,

, gradually supplying pitch for conversion to coke, stirring or agitating the pitch during the conjversion, and continuously discharging coli-efrom the coking chamber.

3. Thev method of distilling" tar to pitchY and `then converting pitch to coke, which comprises bringing the pitch into direct contact with hot coal gasification gases in a stillthereby converting the pitch to coke, stirring or agitating thepitch during the conversion, sprayingthe tar ,intothe hot gases and vapors resulting from the production of the coke to distill the tar to form the pitch, drawing' off the pitch from the tar distillation and feeding it'to the still in which the cokeis produced.

4. The method4 of distilling tar to pitch and Vr'then converting the pitch to coke in hot coal distillation gases, which comprises bringing the pitch into direct contact with the hot coal distillation gases to distill the pitch and produce Ncolsce therefrom, andf then spraying the tar into v-directandV intimate contact with the resultingV gasesand vapors whereby theA tar is distilled to produce the pitch and entrained impurities are removed.E from the gases andi vapors, and thereafter' cooling the. gases and vapors to separateclean distillate therefrom.

5; The continuous` method of converting pitch tocoke, which comprises supplying the pitch gradually toone end' of an elongated still, causing theI pitch toV ow progressively th-rough the still` from one end to the other while agitating or tumbling it, introducing hot coal gasification gases intothe other end of the still and causing them to ow throughr the still countercurrent to the flow of the pitch, whereby oils are progressively distilled from the pitch and the pitch is converted into coke, stirring or agitating the pitch during the conversion, and continuously discharging the coke from theV still.

'6. The improved process of distilling tar and of "-lproducing distillate oils and coke therefrom which comprises subjecting the tar to distillation ma plurality of stages, in one stage bringing the tar into direct and intimate contact with hot coal I gasification'. gases to distil-l the greater part of the -oil content from the tar and in the other stage hot gases, simultaneously producing gas and additional distillate, and cooling the gases respectheconversion of pitch to coke, means kfor pass-Y ing hot gases through each of said stills in direct contact with the tar or pitch contained therein, means for supplying tar to one of said stills, means for withdrawing pitch from said still and introducing it to the second of said stills, means for withdrawing coke fromv the second of said' stills, and means for withdrawing from each ofA said stills the admixed gases and vapors and for cooling the'same to condense oils therefrom.

8. Apparatus for the distillation of tar and the production of coke, gas andy clean distillate oils therefrom comprising a source of hot coal gasification gases, means for bringing partially distilled tar or pitch into direct and intimate contact with the'hot gases at a sufciently high temperature to distill volatile constituents therefrom and produce coke, means for bringing tar into direct contact with the resulting gases and vapors in the form of an intensive spray to detar the gases and vapors and simultaneously distill the tar to produce said partially distilled tar or pitch, and condensing means for cooling the detarred gases and vapors to produce distillate oils therefrom.

9. Apparatus for the distillation of tar and the production of coke, gas and distillatel oils therefromr comprising two stills, means for passing hot gases into the first still, means to supply distillation residue from the second still to the first still, means for continuously dischargsecond still for producing an intense spray of tar in the gases passing therethrough.

10. .The process of distilling tar and producing distillateoils and coke therefrom, which comprises bringing the tar into direct and intimate Contact with hot coal gasification gases to distill offk oilv from the tar and produce a pitch residue' and distillate oilf vapors, bringing the pitch residue into direct contact with hot coal gasification gases so as to coke the pitch residue and produce gas and distillate oil vapors, withdrawing the hot gases and distillate oil vapors from the tar distillation step, withdrawing hot gases and distillate oil vapors from the coking step, and cooling the gases and vapors to condense distillate oils therefrom.

l1. The process of distilling tar and producing distillate oil and coke therefrom, which cornprises bringing the tar into direct and intimate contact with a mixture of hot coal gasification gases, gas, and distillate oil vapors in a tar still to distill oils from the tar and produce a pitch residue, bringing the pitch residue into direct Contact with hot coal gasification gases so as to coke the residue and produce gas and distillate oil vapors, withdrawing the resultant mixture of coal gasification gases, gas, and distillate oil vapors and bringing it into contact with tar in the tar still, withdrawing the hot gases and vapors from the tar still, and cooling them to condense distillate oils.

STUART PARMELEE MILLER. 

